An RAF Typhoon aircraft of the type that escorted a passenger plane into Stansted Airport in southern England following an incident on board Friday. / AP

by Kim Hjelmgaard, USA TODAY

by Kim Hjelmgaard, USA TODAY

LONDON â?? Two British men have been arrested after Royal Air Force fighter jets escorted a civilian plane carrying nearly 300 passengers from Pakistan to the United Kingdom that was diverted to Stansted Airport, officials said Friday.

A British security official told the Associated Press that the situation involving the Pakistan International Airlines flight did not appear terror-related, but the incident further rattled the United Kingdom just days after a soldier was killed on a London street in a suspected terror attack.

The security official requested anonymity because he was not authorized to discuss the investigation.

PIA Flight P709, a Boeing 777 traveling from Lahore to Manchester, was isolated on a runway after it landed at Stansted, on the outskirts of London, at 2:15 p.m. (9:15 a.m. ET). Essex police said two British nationals, ages 30 and 41, were arrested on "suspicion of endangerment of an aircraft."

"This incident is being treated as a criminal offense," a police statement said. adding that "at this point in time no suspicious items have been recovered."

A Pakistani official briefed by British police and PIA security told the AP that the two suspects, speaking Urdu, allegedly threatened to "destroy the plane" after an argument with crew. The official spoke on condition of anonymity because he was not authorized to speak about the case on the record.

Airline spokesman Mashood Tajwar toldThe New York Times that the men threatened to "blow the plane up" but that they later said "they were joking."

Passenger Nauman Rizvi told Pakistan's GEO TV that two men who had tried to move toward the cockpit during the flight were handcuffed and arrested once the plane landed. Rizvi said that after the men were taken away, the flight crew told passengers there had been a terrorist threat and that the pilot had raised an alarm.

After receiving instructions from British security, Tajwar told Sky News, traffic controllers in Manchester contacted the pilot 25 minutes before its scheduled landing. The aircraft then turned north and headed back over the North Sea before heading south to Stansted.

The Ministry of Defense confirmed that two Typhoon jets were scrambled from the RAF station in Coningsby but gave no other details. Defense officials said such escorts are standard when pilots transmit emergency codes.

All passengers were removed from the plane but had to leave their belongings behind. Stansted Airport has since resumed normal operations.